Interrogation of a clinical cohort of 161 affected individuals with nystagmus and/or albinism (Southampton cohort) (including individuals previously reported by Norman et al. and O’Gorman et al.13,27) identified 71 individuals with two pathogenic or likely pathogenic variants (molecularly diagnosed including TYR, OCA2, GPR143 and PAX6 genes), 51 individuals carrying only a single likely disease-associated TYR variant with no candidate pathogenic variants identified in other OCA genes (missing heritability), and 39 individuals with no disease-associated TYR variants. The gene discussed is OCA2; the disease is pathologic nystagmus.